Integrated circuit packaging technology has seen an increase in the number of integrated circuits mounted on a single circuit board or substrate. The new packaging designs are more compact in form factors, such as the physical size and shape of an integrated circuit, and providing a significant increase in overall integrated circuit density. However, integrated circuit density continues to be limited by the “real estate” available for mounting individual integrated circuits on a substrate. Even larger form factor systems, such as personal computers, compute servers, and storage servers, need more integrated circuits in the same or smaller “real estate”.
Particularly acute, the needs for portable personal electronics, such as cell phones, digital cameras, music players, personal digital assistances, and location-based devices, have further driven the need for integrated circuit density. Modem portable electronic devices require a seamless integration of analog and digital subsystems. High-speed digital systems may switch at a high rate, such as more than on gigahertz. At such switching speeds, switching currents radiate energy (noise) that interferes with sensitive analog circuits. Interference usually takes the form of signal crosstalk.
Electromagnetic interference (EMI) is a generic term for unwanted interference energies either conducted as currents or radiated as electromagnetic fields. EMI can emanate from electronic devices in several ways. Generally, voltages and currents in board mounted, integrated circuits create electric and magnetic fields that radiate from the device. EMI radiating from such devices will vary in field strength and impedance according to the shape and orientation of the conductors, the distance from the conductors to any shielding provided by circuit components or by coupling to circuit components.
As electronic devices and integrated circuits operate at higher and higher frequencies, EMI extends into the radio frequency spectrum and can cause significant interference with radio and television signals.
One typical scheme has been to provide a conductive enclosure to an electronic device so that EMI field lines will terminate on such enclosure. Unfortunately, conductive enclosures that contain the entire product or parts of the product can be very expensive. In addition, the need to increase integrated circuit density has led to the development of multi-chip packages in which more than one integrated circuit can be packaged. Typically, these multi-chip packages have integrated circuits mounted horizontally with each having an EMI shield. This increases the size of the package as well as prohibits stacking configurations of the integrated circuits.
Thus, a need still remains for a shielded stacked integrated circuit packaging system having a shield with low cost manufacturing, improved yield, and decreased size. In view of the ever-increasing need to save costs and improve efficiencies, it is more and more critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.